From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 671B42ECD16; Tue, 22 Jul 2025 14:14:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753193691; cv=none; b=oz6+QU7w78WILJe31gAKTpaOPW2nw/AJ+9xYEATanAg1Uj8guKGm1EsxfVt3I0kf3r82rYAaX9scjNohIlYzNlqqSUE66c5X55KKtMP6Lh60heUvEE8ZjU3A2QPxVr44QYYZJYeJpVHNghQy6Rrzn/xyaj/RXmCZR5trUbFTRBM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753193691; c=relaxed/simple; bh=u1m2cKgmEcV+2UMmfk9vm0afPF634E7wmey2dUAAHrs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IWtylT0sYixGzu3qyWH4UwcoZMLSIFFQSvzvgfy4v0DRNoDefl5fhoVtKzBuaQs+UA1GWYrKrnuHjLUhtjfXbwq+mizVKYOJNU1Z7XwFYtLm3v1fHyVCN+GTlDDo0rRjeaS2vJEMLgMVFmXMUSxINP2h52UuzbzZDx5mcXSZC6k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=a+9+BXu6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="a+9+BXu6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D0E7C4CEEB; Tue, 22 Jul 2025 14:14:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1753193690; bh=u1m2cKgmEcV+2UMmfk9vm0afPF634E7wmey2dUAAHrs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a+9+BXu6LmPGxFinQtIJ73sB7t9rQbFuT0Ap+zherVglzdDdhNCqLaAiGzzUdccSA ckRZHSUUgzrIsUOwZzv6CZStYIxwzvSmyMVyHVm/NJFO3rvHCOvhcyArgTuyJaOIPO 2rOjR4Eqqe+YhbzcEjpU0h1SlacEUdyI9h93p38I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christoph Paasch , Tariq Toukan , Gal Pressman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.15 141/187] net/mlx5: Correctly set gso_size when LRO is used Date: Tue, 22 Jul 2025 15:45:11 +0200 Message-ID: <20250722134351.038202384@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250722134345.761035548@linuxfoundation.org> References: <20250722134345.761035548@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christoph Paasch [ Upstream commit 531d0d32de3e1b6b77a87bd37de0c2c6e17b496a ] gso_size is expected by the networking stack to be the size of the payload (thus, not including ethernet/IP/TCP-headers). However, cqe_bcnt is the full sized frame (including the headers). Dividing cqe_bcnt by lro_num_seg will then give incorrect results. For example, running a bpftrace higher up in the TCP-stack (tcp_event_data_recv), we commonly have gso_size set to 1450 or 1451 even though in reality the payload was only 1448 bytes. This can have unintended consequences: - In tcp_measure_rcv_mss() len will be for example 1450, but. rcv_mss will be 1448 (because tp->advmss is 1448). Thus, we will always recompute scaling_ratio each time an LRO-packet is received. - In tcp_gro_receive(), it will interfere with the decision whether or not to flush and thus potentially result in less gro'ed packets. So, we need to discount the protocol headers from cqe_bcnt so we can actually divide the payload by lro_num_seg to get the real gso_size. v2: - Use "(unsigned char *)tcp + tcp->doff * 4 - skb->data)" to compute header-len (Tariq Toukan ) - Improve commit-message (Gal Pressman ) Fixes: e586b3b0baee ("net/mlx5: Ethernet Datapath files") Signed-off-by: Christoph Paasch Reviewed-by: Tariq Toukan Reviewed-by: Gal Pressman Link: https://patch.msgid.link/20250715-cpaasch-pf-925-investigate-incorrect-gso_size-on-cx-7-nic-v2-1-e06c3475f3ac@openai.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c index 5fd70b4d55beb..e37cf4f754c48 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -1154,8 +1154,9 @@ static void mlx5e_lro_update_tcp_hdr(struct mlx5_cqe64 *cqe, struct tcphdr *tcp) } } -static void mlx5e_lro_update_hdr(struct sk_buff *skb, struct mlx5_cqe64 *cqe, - u32 cqe_bcnt) +static unsigned int mlx5e_lro_update_hdr(struct sk_buff *skb, + struct mlx5_cqe64 *cqe, + u32 cqe_bcnt) { struct ethhdr *eth = (struct ethhdr *)(skb->data); struct tcphdr *tcp; @@ -1205,6 +1206,8 @@ static void mlx5e_lro_update_hdr(struct sk_buff *skb, struct mlx5_cqe64 *cqe, tcp->check = tcp_v6_check(payload_len, &ipv6->saddr, &ipv6->daddr, check); } + + return (unsigned int)((unsigned char *)tcp + tcp->doff * 4 - skb->data); } static void *mlx5e_shampo_get_packet_hd(struct mlx5e_rq *rq, u16 header_index) @@ -1561,8 +1564,9 @@ static inline void mlx5e_build_rx_skb(struct mlx5_cqe64 *cqe, mlx5e_macsec_offload_handle_rx_skb(netdev, skb, cqe); if (lro_num_seg > 1) { - mlx5e_lro_update_hdr(skb, cqe, cqe_bcnt); - skb_shinfo(skb)->gso_size = DIV_ROUND_UP(cqe_bcnt, lro_num_seg); + unsigned int hdrlen = mlx5e_lro_update_hdr(skb, cqe, cqe_bcnt); + + skb_shinfo(skb)->gso_size = DIV_ROUND_UP(cqe_bcnt - hdrlen, lro_num_seg); /* Subtract one since we already counted this as one * "regular" packet in mlx5e_complete_rx_cqe() */ -- 2.39.5